I am thinking along the same lines, will be interesting to see what feedback you get. My island is dark as well, the ORB hardware on the perimeter may not look good on the island.

My first thought is of course they can! It's your kitchen, do what you love. I am thinking of having my kitchen island a soft green color and all the other cabinets natural. You can bet my pulls will be different on the green one, maybe a porcelain.

You can definitely mix and match finishes in a room, if that's a look that you like. You can use the same style pulls / knobs in a couple different finishes to keep things somewhat unified if you like. Good luck with your project!

In my professional opinion, I say most definitely. For me, I like to think of the kitchen cabinets as more of a utilitarian function. Your island is a piece of furniture. Showcase it. May it special.

I hope my comments have been help. I look forward to seeing pictures of what you chose to do.